Aircraft are often used to spread material over a surface, for example, in agricultural, firefighting, forest seeding, and other applications. In traditional spreading systems, a gatebox stores and regulates the flow of material from an aircraft. Existing gateboxes generally comprise an opening that allows material to flow out of the gatebox, a hopper portion that stores material and directs the material to the opening, and one or two doors that open and close using hinges in order to regulate the flow of material from the gatebox out of the opening. Some gatebox systems are operable to receive a seeder plate that fits over an opening of the gatebox and limits the flow of material from the opening. Traditional seeder plates are not designed for specific gateboxes, but are after market additions that are attached to the gatebox with a number of bolts.